Electrically-operated burner-controlling apparatus



Nov. 2 1926. 1,605,299

H. w. SWEATT -r AL ELECTRIGALLY OPERATED BURNER CONTROLLING APPARATUS Filed August 6, 1925 5 Sheets-Sheet 1 Ea Z71 {07 5 MMOwM/JWEA 7'T FREDEIWCIIJfiEA UON 7 Nov. 2 1926.

H.v W. SWEATT ET AL ELECTRIGALLY OPERATED BURNER CONTROLLING APPARATUS Filed August 6' 1925 5 Sheets-Sheet fm em om HAROLDMJWEATT FREDE/P/CKJDEN/JON' 575M, 6 MM ATTORNEY:

H. W. SWEATT ET AL Filed August 6. 1925 5 Sheets-Sheet 5 liven z ors HAROLDWSWEA TT FEEDER/C/IJDEN/JON Nov. 2 1926.

ELECTRICALLY OPERATED BURNER CONTROLLING APPARATUS Nov. 2 1926.

H. w. SWEATT ET AL ELECTRICALLY OPERATED BURNER CONTROLLING APPARATUS Filed August 6, 1925 5 Sheets-Sheet 4 THERMOSTAT RECYCLEH' 32/86 *(93 67 /02 q /07 4: #44 5 I MOTO sw Tc/v /0 jg a 4/ 46 Q 7 9 J L 1.9 5) *1 a5 46 3 V 7 43 44 4 42 m4 H 9/ 6E 57 4 SAFETY SWITCH cog-rm MOTOR 5 g 52 w 6 BURNER 6 W/l/l/Il/lll/II/l/ BURNER MOTOR 7 L [raven 2, 01: 7 HAROLD WJWEATT FREDER/c rJDE/ IJOM FIG/5 1 1a (iii-WM ATTORNEY-3 Nov. 2 1926. 1,605,299

H. W. SWEATT ET AL ELECTRIGALLY OPERATED BURNER CONTROLLING APPARATUS Filed August 6, 1925 5 Sheets-Sheet 5 THE/PMOSTA T RECYCLE'R v as,

Pl/Jh GUTTON J PNER 0701? 3: [Tu/anion 3e sum? fmfioLo l/l/JWEATT firfof/rlclriDfi/wsm/ F7614 7501, WM

l-r-ramve vs" Fatentecl Nov. 2

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"HAROLD W. SWEAT'I AND FREDERICK S. DENISON, OF MINNEAPOLIS, MINNESOTA, as- SIGNORS T MINNEAPOLIS HEAT REGULATOR COMPANY, OF MINNEAPOLIS, MIN- NESOTA, A CORPORATION OF MINNESOTA.

ELECTRICAILY-OPERATED BURNER-CONTROLLING APPARATUS.

Application filed August 6, 1925.

This invention relates to new and useful improvements in electrically operated controlling apparatus particularly adapted for use in connection with such structures as,

t for instance, liquid fuel burners, to automatically control the operation thereof, and more particularly relates to such an apparatus having means for preventing burner resumption in the'event of ignition failure,

and which apparatus is also provided with a recycling mechanism cooperating with a control device after temporary power failure, to cause the burner motor to resume normal operation.

Broadly, the object of the invention is to provide an improved electrically operated burner controlling apparatus comprising a burner motor and a control motor adapted to operate a switch to close a circuit to the burner motor for a predetermined interval and thereafter to open it. A safety switch is also provided which is responsive to normal burner operating conditions to maintain a closed circuit to the burner motor, until opened by the control motor, the operation of which may be controlled by remote control by a thermal device such as a thermostat, located in an adjacent room.

A recycling mechanism is also provided which is electrically connected to' the control motor in such a manner as to automati' cally cause said motor to complete its starting cycle to start the burner motor after temporary power failure.

The particular object of the invention, therefore, is to provide an improved electrically operated burner controlling apparatus adapted for use to automatically control a burner motor or similar device.

Uther objects of the invention will appear from the following description and the accompanying drawings and will be pointed out in the annexed claims.

In the drawings there has been disclosed a 45 structure designed to carry out the various objects of the invention, but it is to be understood that the invention is not confined to the exact features shown as various changes may be made within the scope of the claims which follow.

In the drawings:

Figure 1 is a vertical sectional view on the line 1--1 of Figure 2, showing the general construction of the control motor;

' R Figure is a plan view of Figure 1, show- Serial No. 48,656.

ing the contact fingers and the rotary contact member;

Figure 3 is a cross sectional view on the line 3-3 of Figure 1, showing the means provided for operating the contact member and the motor switch shaft;

Figure 4 is a similar View on the line 4-4 of Figure 1, showing the switch mechanism provided for closing the burner motor clrcuit;

Figure 5 is an enlarged detail sectional View showing the snap action provided in the construction of the motor switch to cause said switchesto instantly break their connection with the stationary contacts upon opening of the switches;

Figure 6 is a sectional view on the line 6-6 of Figure 1 showing the commutator of thehmotor and the brushes in contact therewit Figure 7 is a similar view on the line 77 of Figure 1 showing the preferred method of mounting the windings in the motor;

Figure 8 is a sectional view on the line 8-8 of Figure 1- showing the recycling mechanism;

Figures 9, 10 11 and 12 are diagrammatic views illustrating the various positions assumed by the burner motor switches during a complete cycle of operation of the control motor;

Figure 18 is a wiring diagram showing the parts in oil position, ready to commence the starting cycle when the movable contact of the thermostat engages the starting contact; and

Figure i lis a similar view showing the parts in on position, or the position assumed when the burner is operating.

In describing the construction and operation of this novel control apparatus and its associated parts such as the recycling mechanism and the burner motor switches, the control motor, including the above mentioned recycling mechanism and motor switches, will first be described in detail, after which the construction of the safety switch and other parts will be described and their operation in conjunction therewith.

The form of control motor here shown comprises a rotor 21 mounted upon a shaft 22 which is rotatably mounted in suitable bearings 23 and 24 provided in a bearing bracket or end-cap 25 and the intermediate casing wall 26, respectively, are shown in Figure 1. The bearing bracket is suitably secured to the casing 27 by such means as bolts or screws 28, shown in Figures 2 and 6. A commutator 29 is also mounted upon the shaft 22 and is electrically connected to the rotor 21 as is. customary in structures of this type. The rotor 21 is concentrically mounted in the stator 31 in spaced relation thereto so as to provide the usual air-gap therebetween, as shown in Figure 7. Field coils or windings 32 are mounted in insulated relation upon the stator31 to supply energy to the rotor 21. These coils are connected in series and have conductors 33 and 34 leading therefrom to a suitable source of supply, such as the conductors 35 and 36 of the supply circuit, shown in Figures 13 and 14. The rotor 21 and stator 31 are constructed of laminated metal as is customary and well-known in electrical devices of this type.

An important feature in the construction of this novel control motor resides in the provision of a rotatably mounted instrumentality or contact member mounted in the upper portion of the motor casing 27, and which is operatively connected to the rotor shaft 22. This instrumentality or contact member preferably comprises a cylinder 37 having a plurality of contacts 38, 39, 41 and 42 provided thereon, which are adapted to be engaged, respectively, by a like number of flexible contact fingers 43, 44, 45 and 46 (see Figure 2). An annular contact 47 is also provided on the cylinder 37 adapted constantly to be in electrical engagement with a contact finger 48. This finger 48 is mounted upon a terminal post 49 to which one end of a conductor 51 is electrically connected. The other end of this conductor is connected to one of the brushes 52, which is yieldably held in. electrical contact with the periphery of the commutator by means of aspringactuated arm 53. The other brush 52 has a conductor 54 connecting it with the terminal post 55 to which the contact finger 43 is secured (see Figures 1 and 2). The contact fingers 44, 45 and 46 are similarly mounted upon terminal posts 56, 57 and 58. The cylinder or contact member 37 is secured to a shaft 59 which is rotatably mounted in bearings 61 and 62 provided in the bearing brackets or end-caps 25 and 63, the latter being secured to the casing 27 by means of similar bolts 28 as shown in Figure 2.

The means provided for operating the shaft 59 consists of a train of gears mounted within the casing 27 and operatively connecting the reduced end-portion 64 of the motor shaft 22 with the shaft 59 (see Figures 1 and 3). A pinion 65 is mounted upon the reduced end-portion 64 of the rotor shaft 22 and meshes with a gear 66 having a pinion 67 thereon meshing with a similar gear 68, which also has a pinion 69 secured thereto. This pinion meshes with a gear 71 which also has a pinion 72 secured thereto and adapted to mesh with a gear 73 meshing with a pinion 74, as shown by the dotted lines in Figure 3. The pinion 74 is secured to the relatively smaller gear- ,37 will cause the contacts thereon to be moved in and out of electrical connection with the contact fingers as will hereinafter be described.

The control motor above described is of the repulsion type and it is therefore well known to those familiar with the art that to start such a motor it is usually necessary to short circuit the brushes 52, which in this case is accomplished by the contact member 37 operating in connection with a thermal device and a recycling mechanism as will subsequently be described. The thermal device may be such an apparatus as a thermostat located remote from the control motor as, for instance, in an adjacent room, so that temperature variations in the room will cause the thermostat to start the control motor at a predetermined temperature to start the burner motor or to inter- 'rupt its operation.

This thermostat is diagrammatically shown in Figures 13 and 14, and comprises a thermo bar 78 mounted upon .a post 79 and having its flexible endportion adapted to engage a pair of relatively fixed contacts 81 and 82. The post 79, supporting the thermo bar 78, is electrically connected to 'the terminal post 55 of the control motor by means of a wire 83, and the stationary contacts 81 and 82 are similarly connected to the posts 56' and 57 of the control motor by wires 84 .and 85, respectively (see Figures 13 and 14) The purpose of the thermostat is to effect the.

one end connected by a wire 87 to the termi nal post 58'. The other end of the coil 86 has a wire 88 connecting it with one end of a small coil or winding 89 which is inductively connected with the field windings 32 so thatfinduced current will" flow .therethrough when its circuit is closed. The other end of the coil 89 is connected by a wire 91 to the terminal post 49 as shown in Figures 1, 13 and 14; The coil 89 is relatively small in size and may be mounted adjacent one of the field coils 32 as shown in Figures 1 and 7. The relay coil 86 may be suitably supported by means of a bracket 92 secured to the raised portion 93 of the casing 27 as shown in Figures 1 and 2. A movable contact arm 94 having a contact tip 95 thereon is pivotally mounted upon a post 96 mounted in insulated relation upon a plate 97, as shown in Figures 2 and 8 andon which plate the previously described terminal posts 49,. 55, 56, 57 and 58 are similarly mounted,

so as to prevent short circuiting of the cur:.

rent between the posts. The plate 97 is suitably mounted upon the upper portion of the casing 27 and is secured thereto by means of screws 98. A relatively fixed contact point 99 is also mounted in the plate 97 and is adapted to be engaged by the contact tip 95 on the movable arm 94 when the relay coil 86 is tie-energized. This contact point is similarly insulated from the plate 97. The movable arm 94 is electrically connected by a wire 101 to the wire leading from the fixed contact 82 of the thermostat, and the relatively fixed contact 99 is similarly connected by a wire 102 to the wire 83 of the thermostat. The air gap between the movable contact tip and therelatively fixed contact 99 is such that when the two contacts are moved intoelectrical engagement with each other, as a result of the deenergization of the coil 86 caused by tem-' p'orary power failure or interruption of the flow of current through the relay circuit, the air gap between the removable arm 94 and the lower portion 103 of the coil 86 will be sufiiciently wide to prevent the arm 94 from being attracted by the coil to open the circuit between the contacts 95 and 96 when the relay coil 86 is again energized. Means are, therefore, provided for mechanically raising or lifting the arm 94 so as to bring it into the magnetic field of the coil 86 after whicbit will be attracted by the coil .and raised to the position shown in Figures 8 and 14. Under normal operating conditions the movable arm 94 will be held in the raised position shown in the above mentioned figures.

The means provided for mechanically lift ing the arm 94 into the magnetic field of the coil 86. preferably consists of a cam 104 mounted upon the cylinder 37, and which is adapted to engage a depending lug 105 secured to the arm 94, thereby to raise it sufficiently to cause it to be attracted by the coil 86 to its inoperative position shown in Figures 8 and 14/ The purpose of this recycling mechanism is to provide means for automatically starting the control motor to a member 37 is mounte complete its starting cycle of operation after temporary power failure, should the supply of electrical energy to the control motor accidentally be interrupted during the period when the control motor is in the on position and the burner motor is operating as shown in Figure 14. During the off position of the control motor,- and when the burner motor switches are in open position as shown in Figure 13, the fiow-of current through the relay coil 86 will be interrupted as a result of the wire 87 leading therefrom to the terminal post 58' being open between the contact 42' and the flexible finger. 46. The purpose of thus openin the relay circuit when the control motor is in off position is primarily to prevent unnecessary consumption of current during such position or cycle of operation. A cover or closure ispreferably provided to cover the recycling mechanism and also the rotary contact member 37 and its complementary contact fingers.

The means provided for controlling the flow of current to the burner motor consists of a starting switch 106 and a running switch 107 preferably mounted'on ,an insulating'plate 108 within the casing of the control motor, and which switches are operatively connected to the rotor shaft 22 and also to the shaft 59 u on which the contact.

To'differentiate between these two motor switches the former will hereinafter be referred to as the starting switch and the latter as the running switch. The starting switch 106 and the running switch 107 are pivotally connected to a conductor strip 109 having a wire 111 leading therefrom to the conductor33 connecting the field winding 32 of the control motor with the supply circuit. Thus the two switch arms 106 and 107 are constantly in electrical connection with the supply circuit. Relatively fixed contact blades 112 and 113, preferably flexible, are alsomount .ed upon the insulating plate 108. The

starting switch blade 112 has a wire 114 .14. A wire 117 leads from the flexible con- 1 tact blade 113 to a safety switch mechanism which will subsequently be described.

The swit h arms 106 and 107 are each provided with an anti-friction roller 118 adapted to ride upon a pair. of cams 119 and 121, mounted upon a relatively short 5, thereby causing the s shaft 122 as shown particularly in'l igure 1. One end of this shaft is borne by a bearing 123 mounted in the insulating plate 108 upon which the switch arms are mounted, and the other end of the shaft is mounted in a bearing 12-1 provided in the end cap 63. The cam 119 is adapted to actuate the starting switcharm 106 and the cam 121 is adapted to actuate the running switch arm 107. The rollers 118 of the switch arms 106 and 107 are yieldably held against the periphery of the cams 119 and 121 by means of asuitable spring l'IlGIIllJGl 125 mounted upon the pivots of the two switch arms and having its ends seated against lugs or hooks 126 as shown in Figure 1. This spring member 125 is adapted to exert a constant force against the switch arms 106 and 107 to tend to move them into open position as shown in Figures 9 and 13. A gear wheel 127 is terminallyfmounted unon the shaft 122 and meshes with a similar gear 128 secured to the gear wheel 76 so that when the latter is rotated, the gear 128 will simultaneously be rotated to actuate the cam shalt 122. The cams 119 and 121 are preferably mounted for relative movement upon the cam shaft 122, such movement, however,

beingv limited by means of pins 129 secured to the shaft and having their ends seated in slot 131 provided in the of the two cams as shown in Figure 5. The purpose .of thus loosely mounting the cams upon the shaft 122 is to provide a snap'action for moving the switch arms out electrical engagement with the flexible 112 and 113. Referring to Figure :5 it will he l rs 8 approach rs as indicated by the dotted lines in the ahcve figure, the action of the spring mem e' ing to force the rollers 113 cam shalt 122, will cause the C2111. reia tively rotate or advance upon to the full line positio s o stantly moved out of supplementary blade c, 1 current from arcing hetween the two contacts during the opening movement of the switch, The cams 113 and 1. also so constructed and arranged as t0 properly time the opening and closing the two switches. during each complete cycle of operation of the control motor.

The form of safety switch employed in connection with this novel burner controlling apparatus is preferably of a type adapted to he actuated by the of comhustion so that it he directly res stinsive to hurner con is to open or close the motor circuit. shown is preferably of the u, 2, CO1 mrising a non-condi i which c in, quantity Cu meifiui- .55

period of operation when the control ductive material 13 1 is contained. The wire 117 leading from the switch blade 113 has its other end secured to a post 135, and a similar post 136 is connected by 2. wire 137 to the wire 114. leading from th'e contact blade 112 to the burner motor 1151 The contact posts 135 and 136 inwardly project into the tube 133 so that when the tube is in the position shown in Figure 14, the mercury will engage the ends of both contacts thereby closing a circuit to the motor as follows: from the conductor 33 through the wire 111, conductor strip 109, switch arm 107, contact finger 113, wire 117, post 135, mercury 13%, post 136, wire 137 thence through the wire 114, burner motor 115 and the wine 116, back to the conductor 34, thereby completing the running motor circuit. When the tube 133 is oscillated upon its center 138 to the position shown in Figure 13, the mercury will flow to the opposite end of the tube thereby opening the, circuit between the contact posts 135- and 136 with the resultant interruption of the burner motor. The tube 133 may be supported by an arm 139 having a' tension spring 1 11 connected thereto which tends normally to hold it against a step 112 as shown in Figure 13. The oscillation of the tube 133 to open andclose the hurner motor running circuit, is preferably accomplished by means of the thermal element 143 mounted in such a manner that the heat of combustion may act upon it to move itfrom its inoperative position, shown in Figure 13, to its operative or circuit-closing position shown in Figure @ther forms of safety switches may he employed in place ot'the mere" switch here shown, it losing understood that the orm of: switch emploved must pre'ferahi he a type which will be directly responsive to burner condh tions to inai a closed motor circuit upon normal s From the noted that ploys two c r nits to; c the burne tor; Or 1 only to the motor, and maintain a closed motor circuit du its 7. C3 mo is on tie on po 'ition, as shown in lli are 14. The control motor also employs a plurality of circuits in its operation. The air-- cuits provided by the wires 83, 8 1 and oil the thermostat function only to initially start the control motor at each cycle of op eration. after which a positive running cir cuit will be provided "for control h the closing of the circuit composed of the 51 and 541-, the "post finger as. one of the semicircular contactsSS,contactmember lar contact '7, finger 13 and the pest 4:9

,hove' desc o d circui will short-circuit 5 contrclmct tain a closed running circuit for the motor to complete each cycle of operation, afterthe motor-has been initially started by the room thermostat having engaged one of the contacts 81 or 82. The circuit provided by the recycling mechanism may also function to initially start the control motor to actuate the motor switches "106 and 107 after temporary power failure.

Means are preferably provided for manually starting the control motor to cause it to repeat the starting cycle of operation, should the safety switch fail to close the running circuit to the burner motor as a result of ignition failure, which might be caused by the pilot light or ignition means failing to function when the burner motor starting circuit is closed. Such'means preferably consists of a push button 144 having wires 145 and 146 connecting it with. the wires'83 and 85, respectively, of the thermostat as shownin Figures 13 and 14. Should the ignition means thus fail to function when the motor switches 106 and 107 are closed during the starting-cycle of operation of the control motor, and the control motor reaches the on position with the room temperature calling .for heat; then, after the faulty ignition means has been remedied, the control motor may be caused to repeat its starting cycle of operation to close the burner motorswitches by simply actuating the push button 144. Referring to Figures 13 and 14 it push button circuit, by actuating the button 144, is equivalent to the thermo bar 7 8 engaging I the fixed contact 82 of the thermostat which circuit must be closed to initially start the ontrol motor to repeat its starting cycle of operation.

Operation.

The operation of this novel burner controlling apparatus may be explained with reference to Figures 13 and 14. Figure 13 illustrates, diagrammatically, the position assumed by the parts when in off position and the burner motor is inoperative, and Figure 14 illustrates the parts in on position as when the burner motor is functioning. When the parts are in ofl position, as shown'in Figure 13, the thermo bar 78 may be either temporarily in contact with the post 82 or be positioned between the contacts 81 and 82, as shown, without having any effect upon the control motor. This will readily be seen when it is noted that'the finger 45, connecting the post 82 with the contact member 37, is out of engagement with the contact 41 of the member 37. The thermo bar 78 will'remain in contact with the post 82 as long as maximum room temperature is maintained. Upon dropping of the post 81 as indicated by the arrow. It will also be noted by reference to Figures 13 and 14 that when the contact member 37 is in either off or on position, the brush circuit of the control motor will be open as a result of the flexible contact finger 43 being out of engagement with the substantially semi-circular contacts 38 rovided upon'the rotary contact member The gaps provided between the ends of these two contacts 38 are of suflicient width to cause the fin er 43 to be moved out of contact therewith when in the positions shown. When thus positioned the contact finger 44 will be in electrical connection with the contact 39 so that as soon as the thermo bar 78 engages the contact 81, a brush circuit will be completed and closed as follows: from the contact 81through. the wire 84 to the post 56; thence through the flexible finger 44, contact 39, contact member 37, rotary contact 47, through the flexible finger 48 to the terminal post 49; thence through the wire 51 to one of the brushes 52; from the other brush 52 through the wire 54 to the terminal post 55, wire 83, post 7 9 of thethermostat, through the thermo bar 78 and back to the contact post 81. Such closing of the above described brush circuit will cause the control motor to commence its starting cycle of operation to close the motor switches 106 and 107. Upon the initial movement of the rotary contact member 37, the switch arm 43 will engage one of the semi-circular contacts 38 after which the thermostat will cease to function,

as the brush circuit will then be as follows:

from the brush 52 through the wire 54 to the terminal post 55; thence through the flexible finger 43 to one of the contacts 38, through the contact member 37, rotary contact-47,

started, which will result/if normal conditions exist, the heat of combustion will afi'ectthe thermal element 143 and cause it to engage the arm 13%) and move it to the position shown in Figure 14, thereby closing the circuit between the contact posts 135 and 136 of the mercury tube.

Before the control motor has completed its starting cycle of operation and also before the switch 106 is opened, the running switch room temperature the thermo bar will leave arm 107 is moved into closing position as the contact 82 and will travel towards the shown in Figure 11 so that when the starting 3 switch arm 106 is movedout of engagement with the complementary contact finger 112, a closed circuit will be maintained to the burner motor to cause-it to continue operating as long as the contact member 37 to the control motor is in the on position, shown in Figure 14, and until interrupted by the action of the thermostat in starting the control motor in its next cycle of operation to stop the burner motor. During the starting cycle of operation of the control motor as above described, the Contact 42 will be moved into electrical engagement with the finger 46, thereby causing the coil 86 to become enerized and to remain energized as long as the control motor is in the on position.

As soon as'the'burner motor has thus been started and the room temperature begins to rise, the thermo bar 7 8 will reverse its travel and will leave the contact 81 and move towards the opposite contact 82, as indicated by the arrow in Figure 14. During each cycle of operation of the control motor, the first c cle beinglto start'the burner as above descri ed and the second cycle being to interrupt the burner motor; the contact member 37 will travel one-half revolution'so that when it comes to rest at the completion of the starting cycle of operation the contact 44 will be out of electrical connection with the contact member 37 and the similar contact member 45 will be in electrical connection with the contact 41, thereby electrically connecting the contact member 37 with the fixed post 82 of the thermostat.

When the thermo bar 7 8 engages the contact post 82 the brushes of the control motor be short-circuited to initially start the motor, and the closed brush circuit will be as follows: from the contact 82 through the wire 85,'post 57, finger 45, contact '41, member 37, rotary contact 47, finger 48, post 49, wire 51 to one of the brushes 52; from the other brush 52 through the wire 54, post 55, wire 83 to the post 79'ot the thermostat; thence through the thermo bar '78 and back to the post 82. Such closing of the above described brush circuit to the control motor will cause said motor to be initially started, after which the contact finger 43 will again engage one of the semi-circular contacts 38 which will a ain cause the thermostat to cease its functioning while the control motor will again is completing its next cycle of operation to stop the burner.

The cam 121 is so designed as to cause the running switch arm 107 to be moved out of electrical connection with its complementary blade 113 a predetermined interval after the control motor has commenced its closin cycle of operation. Whenthe two switch.

arms 106 and 107 have thus been moved intocircuitopening position, as shown in Figures 9 and 13, the burner motor will be interrupted and the control motor will continue op-= ncomes crating until the contact member 37 assumes its normal off position as shown in Figure 13.

. During the normal operation of the burner motor, and when the rotary contact member 37 of the control motor is in the on position, as shown'in Figure "14, current will flow through the relay coil 86, thereb causing the movable switch arm "4 to be eld in circuit-opening position as nown in Figure 14. It is to be understood that the cam 104 is so arranged with relation to the lug 105 upon the contact arm 94, that the arm 94 will be moved into the magnetic field of the coil 86 about the time that the contact 42 is moved into electrical connection with the contact finger 46, so that when the contact is made the arm 94 will be attracted by the coil 86 and will thereby be held in the position shown in Figure 14.

An important feature ofthis invention resides in the operation of the recycling mechanism which functions in the event of temporary power failure while the contact member 37 is in the on position, shown in.

Figure 14, and when the burner motor is operating. In the event of such power failure the relay coil 86 will become de-energized allowing the contact/arm 94 to be moved in to electrical connection with the contact 99 thereby closing a brush circuit which will be as follows: from the contact 99 through the wire 102, wire 83, post 55, wire 54, brushes 52, wire 51, post 49, finger 48, contact 47, member 37, contact 41, finger 45, post 57, wires 85 and 101, post 96 and through the movable contact arm 94 back to the gust 99. Thus when power is again applie to the apparatus the control motor will immediately commence its closing cycle of operation and will continue until it reaches its off position shown in Figure 13. Should the room thermostat still be calling for heat or be in electrical contact with the contact 81, then the control motor will go through its next cycle of operation to start stat as a result of the thermo bar engaging the contact bar 82 after the predetermme "room temperature is reached. The recycling mechanism, therefore, provides a means for automatically closing a circuit between the thermostat wires 83 and 85 to cause the control motor to repeat its starting 0 ole of' operation after temporary power ailure, and when the contact member 37 of the control motor is in the on position and the burned motor is .functionin The safety switch providing for maintaining a closed burner motor circuit during the normal operation of the burner also performs an important function in theopera" tion of this novel apparatus. The primary iee purpose of this safety switch is to prevent the burner motor from functioning in the event of ignition failure such as might occur as a result of faulty ignition means, or in case the fuel supply line should become temporarily interrupted and thereafter opened while the burner motor is operating.

It will also be impossible to cause the burner motor to continue functioning if ignition fails to come on upon such initial starting of the burner. This will readily be understood by referring to Figures 13 and,

1 1. In Figure 13 the safety switch is shown in circuit-opening position, the position as.- sumed when the burner is cool or when there is no combustion. In Figure 14: the switch is shown'i'nithe position assumed when combustion-has taken place and the heat of combustion has caused the thermal element 143 to warp and oscillate the mercury tube 133 from the position shown in Figure 13 to the circuit-closing position shown in Figure 14. In the event of temporary power failure and immediate resumption of power thereafter, the burner motor may be immediately started upon the resumption of such power, if the interval of such power failure has not been long enough to cause the thermal element 143 to cool sufficiently to cause the running circuit to the burner motor to be opened. Should the interval of power interruption, however, be long enough to allow the thermal element 143 to cool sufliciently to open the running circuit, then the burner motor will be interrupted and will remain inoperative until the control motor has completed its next starting cycle of operation.

Having thus described our invention what we claim as new and desire to secure by United States Letters Patent is 1. In an electrically operated burner controlling apparatus, the combination of a burner motor, a control motor for the burner motor, a switch operable by the control motor to close a circuit to the burner motor for a predetermined interval and thereafter to open the same, and a safety switch indepen dent of the control motor circuit responsive to normal burner conditions to maintain a closed burner motor circuit. 1

2. In an electrically operated burner controlling apparatus, the combination of a burner motor, a control motor for the burner motor, a switch operable by the control motor to close a circuit to the burner motor for a predetermined interval and thereafter to )pen the same, and a safety switch responsive to normal burner conditions to maintain a closed burner motor circuit, and a recycling mechanism operable after temporary failure of electrical supply during normal running operation of the apparatus to cause said first- Inentioned switch to repeat its function.

3. In an electrically operated burner controlling apparatus, the combination of a burner motor, a control motor for the burner motor, an automatically operable control to start the control motor, means operable by the control motor to render the automatic control inoperative after starting of the con trol motor and to stop' the control motor after a predetermined travel, a switch operable upon said travel of the control motor to close a circuit to the burner motor after a predetermined interval and thereafter to open the same, and a safety switch indepen dent of the control motor circuit'responsivc to normally operating burner conditions to maintain a closed burner motor circuit.

4. In an electrically operated burner controlling apparatus, the combination of a burner motor, a control motor therefor, an automatically operable control to start the control motor, an instrumentality operable by the control motor, means on said instrumentality to render the automaticcontrol inoperable after starting of the control motor, means on said instrumentality to limit the travel of the control motor,a switch operable upon said travel of the control motor to close a circuit to the burner motor for a predetermined interval and thereafter to open the same, and a safety switch in-. dependent of the control motor circuit re'-' sponsive to normally operating burner conditions to maintain a closed burner motor circuit. 7

5. In an electrically operated burner con trolling apparatus, the combination with a burner motor, a control motor therefor, an automatically operable control to start the control motor, an instrumentality operated by the control motor, means on said instrumentality to render'the automatic control inoperable after starting of the control mo-- tor, means also on said instrumentality to limit the travel of the control motor, a switch operable upon said travel of the control motor to close its circuits to the burner motor for a predetermined interval and thereafter to open the same, a safety switch responsive to normally operating burner conditions to maintain a closed burner motor circuit, and a recycling mechanism cooperating'with said instrumentality after temporary failure of electrical supply during'normal running operation of the apparatus to cause said first-mentioned switch to repeat its function.

6. In an electrically operated burner controlling apparatus, the combination of a burner motor, a control motortherefor, an automatically operable'control to start the control motor, an instrumentality operable by the control motor and comprising a plurality of contacts adapted to be electrically connected to the automatic control to render said control inoperative after starting of the control motor, and a recycling mechanism also electrically connected with said autolib matic control and said instrumentality and operable after temporary power failure during noriial running operation of the apparatus,

urner motor.

7. In an electrically operated burner con trolling apparatus, the combination of a burner motor, a control motor therefor, a switch operable by the control motor to close a circuit to the burner motor. for a pre'de terminedinterval and thereafter to open the same, a thermostatically operable control device to start the control motor, an instrumentality operable by the control motor to render the thermostatic device inoperative afterstarting of the control motor, a recycling mechanism operable after temporary power failure during normal running operation of the apparatus to cause said control motor to complete its cycle of operation to startthe burner, said recycling mechanism comprising "a coil arranged in inductive relation to the supply circuit, and having a movable' contact adapted to close a supplementary circuit to start the control motor.

8. In an electrically operated burner controlling apparatus comprising in combination a burner motor, a control motor thereion-starting and running circuits for the burner-motor, a switch mechansm operable.

by the control motor to close the starting circuit and to open the same a predetermined interval thereafter, a safety switch in the running circuit responsive to normally operating burner conditions to close said circuit, and a thermostatically operable device cooperating with the controlniotor to open said burner motor running circuit when a predetermined room temperature is reached.

9. An electrically operated burner control.- ling apparatus comprising in combination a burner motor and a control motor therefor, starting and running circuits for the burner motor, a switch mechanism operable by the control motor-Ito close the starting circuit, a safety switch responsive to nor- .mally operating burner conditions to close the running circuit, a thermostatic device responsive to room temperatures to start the control motor to actuate said switch mecha-' nism, a rotary contact member on the control member having an electrical connection with said thermostatic device, and means on said contact member to provide a positive running circuit for the control motor a predetermined interval after starting regardless of the action of thethermostatic device.

10. An electrically operated. controlling apparatus including control motor, an

to cause said control motor to come, lete its cycle of operation to start. the

armature in'said' motor having a pair of brushes constantly in electrical connection therewith, a winding for sup lying electrical'energy to said armature iavinga connection with a source of supply, a rotary contact member having a plurality of contacts thereon adapted to be moved into electrical engagement with a plurality of flexible contact fingers, a thermostat having electrical connections with said rotary contact memher and functioning to short-circuit the brushes to initially start said control motor, and means on said contact member adapted to short-circuit said brushes and to provide a positive running circuit for the control motor a predetermined interval after having been started by said thermostat.

11. An electrically operated controlling apparatus including a control motor having" anarmature mounted therein, a pair or brushes in electrical connection with said armature and adapted to beshort-circuited to start the motor, a contact member rotatably mounted in said motor, ac-plurality of contacts on the member, contact fingers adapted to be engagedby said contacts, one of said contacts being constantly in electrical connection with one of said brushes, and

another of said contacts being adapted to maintain a closed brush circuit to cause said motor to continue to operate after having been. initially started and thereafter to interrupt the same, and means responsive to temperature changes adapted automatically to initially start said motor.

12. An electrically operated controlling apparatus including a control motor having an armature mounted therein, a pair of brushes in electrical connection with said armature and adapted to be short-circuited to start the motor, a contact member rotatably mounted in said motor, a plurality of contacts on the member, contact fingers adapted to be engaged by said contacts, one of said contacts being constantly in electrical connection with one of said brushes, and another of said contacts being adapted to maintain a closed brush circuit to cause said motor to continue to operate after having been initially started and thereafter to interrupt the same, means responsive totem erature changes adapted automatically to initially start said motor, and a re-cycling mechanism adapted automatically to function after temporary power failure to cause said control motor to repeat its operation.

lln witness whereof, we have hereunto set our hands this third day of August: 1925.

nnriotn w. swna'rr. rnnnnmon s. DENISON.

DlQ CLAlh/IER 1,605,299.Ha-r0Z(Z W. S'weatt and F rederz'e/c S. Denz'son, Minneapolis, Minn. Elmo TRIOALLY-OPERATED BURNER-CONTROLLING APPARATUS. Patent dated November 2,

1926. Disclaimer filed August 28, 1981, by the assignee, Minneapolis-H 0110 2]- well Regulator Company.

Hereby enters this disclaimer to that part of the claim in said specification which is v in the following Words:

6. In an electrically operated burner controlling apparatus, the combination of a burner motor, a control motor therefor, an automatically operable control to start the control motor, an instrumentality operable by the control motor and comprising a plurality of contacts adapted to be electrically connected to the automatic control to render said control inoperative after starting of the control motor, and a recycling mechanism also electrically connected with said automatic control and said instrumentality and operable after temporary power failure during normal runuingoperation of the apparatus, to cause said control motor to complete its cycle of operat on to start the burner motor.

[Ofiiezet Gazette September F32, 1931.]

DESCLAIMER 1,605,299.Hm"0Z(Z W. Sweatt and Frederick S. Denison, Minneapolis, Minn. ELEC- TRIOALLY-OPERATED BURNER-CONTROLLING APPARATUS. Patent dated November 2, 1926. Disclaimer filed August 28, 1931, by the assignee, llli-nneapolis-Honaywell Regulator Company.

Hereby enters this disclaimer to that part of the claim in said specification which is I in the following Words:

6. In an electrically operated burner controlling apparatus, the combination of a burner motor, a control motor tl1erefor,an automatically operable control to start the control motor, an instrumentality operable by the control motor and comprising a plurality of contacts adapted to be electrically connected to the automatic control to render said control inoperative after starting of the control motor, and a recycling mechanism also electrically connected with saidautomatic control and said instrumentality and operable after temporary power failure during normal running operation of the apparatus, to cause said control motor to complete its cycle of operation to start the burner motor. Y

[Oficial Gazette September 22, 1,931.] 

